How to specify 64 bit integers in c
Try an LL suffix on the number, the compiler may be casting it to an intermediate type as part of the parse. See http://gcc.gnu.org/onlinedocs/gcc/Long-Long.html
long long int i2 = 0x0000444400004444LL;
Additionally, the the compiler is discarding the leading zeros, so 0x000044440000 is becoming 0x44440000, which is a perfectly acceptable 32-bit integer (which is why you aren't seeing any warnings prior to f2).